IT Revision.

IT Revision.

1. Data, Information and Knowledge

   • Information: Data which has been processed by a computer system and given context and meaning.
     • Example: Context is times of a 100m race
   • Data: Comprised of raw numbers, letters and values which have been collected that have no meaning.
     • Example: 1,14.2, 2, 13.8, 3, 14.7
   • Knowledge: Derived from information by applying rules to make decisions.
     • Example: Runners - 1 2 3 Times - 14.2 13.8 14.7

2. Encoding.

   • Shortening words down to a small number of letters.
     • Why? We encode data because it is less effort to type in, improves accuracy which makes it easier to check, takes up less storage and more data can appear on the screen
     • Encoding coarsens the precision of the data which means it is less accurate than the data from which it came. This causes a problem due to value judgement in which information is categorized based on someone's opinion which could differ from someone else's view.

3. Value and Importance of information.

   • Good data is accurate (error free), complete (contains all the information that is required to make decisions), and up to date(comes form sources that are new and current)
   • Enables us to: make better decisions to gain a competitive advantage- accurate stock level allows products to be ordered when needed to reduce waste costs.
   • Enables us to: monitor progress to maintain a competitive advantage- Information on sales figures on what the customers like an see what products are selling best. EPOS- can monitor staff.

4. Validation.

   • a computer check that checks that the data entered is sensible and reasonable.
   • Presence check: The computer will reject a blank space which means data must be entered to proceed- e.g. credit card details.
     • Range check: The data entered falls between two set values-e.g. birthday when applying for college places.
   • Format check: The computer checks that the data entered is in the correct format- e.g. email address need "@"
     • Data Type check: The data inputted is the correct type- e.g. date, number or text.

5. Verification.

   • a human check that checks whether the data entered is the same as the source data.
     • Double data entry: The data is entered twice and if they match then they can continue the process.
       • Printouts: a physical copy is made and checked for errors.
     • Proof reading: the data is re-read to check for mistakes and make sure it compares with the source data.

6. Advantages over manual systems.

   • Repetitive processing- millions of bank statements can be printed.
   • Speed of processing- much faster when doing calculations on spreadsheets
   • Storage capacity- much more records can be held on a data base- e.g. medical records.
   • Speed of searching- - faster- when searching for a speeding car's registration plate.